Subset identification gate circuit



March 22, 1960 R. l... KoEHLER 2,929,880

suBsEI IDENTIFICATION GATE CIRCUIT Filed oct.24, 1955 Qi 3 a; e? Illllniw nnng @www m Ll n 3 .l m kh v v v La l" tu' n Elk I 2,929,830 Meer waarnemen GATE CIRCUIT Robert L. Koehler, Canoga Parli, Calif., assigner to Ralph D. Collins, Beverly Hills, Calif.

Applicatie! More 24, 1955, Serial N01 542.5239 i4 Claims, (Cl, 179-117) This invention relates to communication apparatus such as telephones, and particularly to a subscriber iden-` and"claimed. My application, Serial No. 527,113, filed August 8, 1955, discloses and claims an improvement of the" Collins identifying system, which improvement resides primarily in the frequency generator used at the subset. i The Ypresent invention is directed to a code controlled circuit to prevent the central oihce equipment from responding to transient signals but only to the identifying signal. The code controlled circuit permits the receiving elements to receive the desired signal only at a specified point" in the dialing operation, and at all other points the receiver is locked out to prevent false response from voice 'or other transients. Specifically, the identifying receiver will be electrically opened for receipt of the identifying alternating current frequencies only during the second series of dialA pulses from the subset dial. The circuit also includes multivibrator units which insure that any identifying current will have sufficient amplitude to operate the standard code identifying unit at the central station.

i The principal object of the invention, therefore, is to facilitate the identification of subscriber sets or subsets of a telephone system in a simple, economical, and accu# rate manner.

Another object of the invention is to provide an improved identilication receiver of identifying currents.v

' 'A further object of the invention is to provide a code controlled circuit at the central oilce which prevents false identification of a subscriber station or subset' by unwanted transient signals.

I A still further object of the invention is to provide a atent code controlled circuit at a central oice which is not subject to false signals and which provides sufiicient amplitude of the ydesired signal for accurate operation I of the identifying unit.

The novel features which are believed to be characteristic of this invention, both as to the manner of its organization and the mode of its operation, will be better understood from the following description when read in conjunction with the accompanying drawings, in which: n

Fig. 1 is a block diagram of the complete system em-v bodying the invention; and

Fig. 2 is a combination schematic and block diagram of the central oiiiee equipment embodying the invention.

Referring now to the drawings, and particularly Fig. l, the block 4 represents the subset circuit shown in either of the above-identified pending applications, the subset being connected by conductors 5to central office equipment shown in block 6, which includes the central oice equipment shown in the prior applications as modified by the present invention shown in Fig. 2.Y

Block 81 is a standard code unit used at the central station and shown in the prior and present applications.

Referring now to Fig. 2, the dial impulses and the identifying currents are received over conductors 5 whichV energize the subset from a battery 35 over pulsing relay windings 36 and 46. The received identification signals are impressed over conductors 54 on a concentrator unit` 57, then on a limiting amplifier 55 and an attenuating pad S6, and then on the inputs of a plurality of filters 58, 59, 60, 61, and 62. The identifying numerals for thesev elements are the same as those used in my co-pending ap# plication, Serial No. 527,113, mentioned above, to aidA in identifying the common elements of the systems.

The filters vjust mentioned are connected to new'circuit elements, namely, multi-vibrators 20, 21, 22, 23, and 2'4, which are then connected to their respective rectiers; 63, 64, 65, 66, and 67. Therectiliers are then connected to their respective thyratrons 69, 70, 71, 72, and 73 with their respective bias batteries and grounds. The anodes of the thyratrons just mentioned are connected toy their respective relays '75, 76, 7'7, 78, and '79, which instead of being connected directly to their polarizing batteries now include a plurality of respective contacts 82, 83, 84, 85, and 86 actuated by respective solenoids S8, 89, 90, 9,1, and 92. The actuation of the solenoids 88 to92, `inf elusive, will close their respective contacts 82 to 86, inclusive, which will energize the respective relays to 79, inclusive, when the thyratrons lire, for closing theirk respective contacts 94, 95, 96, 97, and 9 8. The closing of these last-mentioned contacts will provide the desired actuation of the code identification unit in the well known manner. Although only ive'channels are shown,n

prevents unwanted transient signals, such as voice or other unwanted impulses from falsely operating the codel identification unit, the pulsing relay windings 36-46 vareV energized immediately upon the removal of the handset" at the subscribers station and the direct current will close contacts 10 and open contacts 11 of this pulsing relay. The closing of contacts 10 energizes relay B to prepare an energizing circuit for relay C over contacts 12, contacts l1 when closed, conductor 7, and battery 8. Now when the dialingcam at the subset breaks the direct current circuit of pulsing relay 36--46, this relay will be dre-energized, which will occur each time the dialing cam breaks its contacts.

The de-energization of the pulsing relay will permit its contacts 11 to close to energize relay C over the circuit described above. Relay B is a slow release relay and thus remains energized during the open periods of ap` proximately 60 milliseconds of any series of pulses from the dialing cam. Thus its contacts 12 remain closed during an entire series of dialing pulses. So for each time that pulsing relay 36-46 is de-energized during' any series of pulses from the subset dial, pulses are im'- pressed on relay C over contacts 11 and 12. Relay C is also a slow release relay so` it will not follow any series of dial pulses but will remain energized during any train of pulses from the pulsing relay 36-46. A train of pulses may consist of any number from one through ten, each of which is approximately 40 milliseconds duration;

The first energization of relay C closes its contacts 13 to energize a motor magnet MM over battery 9 to activate a mechanical driving cam on a sequence switch Patented Mar. 22, 196i),

14 having a rotary contacter 19 and ten contact elements. This motor magnet operates by cooking the driving cam upon its energization, and upon the de-energization thereof permits a spring to move the contacter 19 toits next contact element. The normal position of contacter 19 is on contact 1, and the first energizatien and deenergization of MM will move it to its secondcontact. Itis moved to its second contact element at the end of the rst series or train of impulses, at which time relay C is de-energized, due to pulsing relay 36-46 remaining energized and holding contacts 11 open because the handset at the subscribers station is still removed.

Upon movement of contacter 19 to its second contact element, relay D isenergized over conductor 25 and battery 26. The energization of relay D closes its contacts 15 and 16 and prepares an operating circuit for relay E, which will become operative on the tirstbreak pulse of the second series or train of dial pulses from the subset dial. kThe closing of contacts 15 of relay D will not energize either relay C or relay E because interconnected batteries 8 and 27 have opposing polarities. However, the first open pulse on the second series of dial pulses from the subset de-energizes pulsing relay 36-46 which permits the closing of contacts 11 to relay C and ener gizes motor magnet MM las above described. Simultaneously, relay E is new energized from battery 27 over contacts 15, conductors 3G and 7, contacts 11 and contactslZ.

. The energization of relay E closes its contacts 18 and thuscompletes its locking circuit from battery 27 over conductor 31, contacts 18, conductor 32 and contacts 16. A rectilier 28 in the circuit of relays C and E prevents inverse current feedback to relay C over contacts 16 and 1,8. The operation of relay E also closes its contacts 17 which energizes solenoids 88 to 92, inclusive, from battlery 29, which places polarizing potential en the respective thyratrons 69 to 73, inclusive, by closing respective contacts 82 to 86, inclusive. This action closes code unit contacts 94 to 98, inclusive. Thus, the channel receiving an identification tone through its respective lter willbe connected to code unit S1.

New at the end of the subset dial, the motor magnet MM is again de-energized to move the contact 19 elf its second'contact element and relay D is de-energized and its contacts 15 and 16 are opened. This de-energizes relay E by breaking its holding circuit contacts 16, which breaks contacts i8 and 17. The breaking of contacts 17 de-energizes relays 88 to 92, inclusive, which breaks contacts 32 to 86, inclusive. This action removes polarizing voltages from the thyratrons 69 to 73, inclusive.

, Thus identifying pulses from the various subsets are received at the code identiiication unit S1 only during the lsecond series of pulses of the subset dial and any transient pulses in the subsciibers line caused by voice or other sources are not transmitted to the unit 81. In this manner, there is ne false identification of any particular subset, each having its own frequency which will be transmitted te its respective multi-vibrator by the lters 58 to 62, inclusive. -I claim:

l. A code controlled circuit for a telephone subscribers subset identification system comprising a plurality of transmission circuits, a pulsing relay adapted to be energized by the dialing pulses from said subset, a pair of contacts, one of which is adapted te be made and another broken upon energization of said pulsing relay, a first slow release relay energized by the energization of said pulsing relay, a second slow Arelease relay adapted to beenergized upon the de-energization of said pulsing relay, -a step mechanical contacter having a plurality of contacts and energized by the operation of said second slow release relay, a relay energized by the malting of a certain contact of said mechanical contacter, and a relay energized by the energization of said relay the second series of impulses from*V energized by said mechanical contacter for making operative said plurality of transmission circuits.

2. A code controlled circuit in accordance with claim l in which said mechanical contacter closes a connection at only one step position, and said last mentioned relay is locked energized until the de-energization of said relay energized by said mechanical contacter.

3. A code controlled circuit for a telephone subscribers subset identification system comprising a plurality of circuits, each circuit being receptive to a particular frequency from one of a plurality of said telephone subscribers subsets, said circuits including respective thyratrons, a plurality of polarizing circuits for said thyratrons adapted to be closed and opened, a pulsing relay responsive to dialing pulses received from said telephone subsets, a step mechanical contacter adapted to close a relay circuit at one step position thereof upon a predetermined series of dialing pulses from said subsets,l and a plurality off intermediate relays for advancing said con-- taeter one step for each series of dialing pulses."`

4. A code `controlled circuit for a telephone subscribers ysubset identification system for permittingdifferent frequency identilication signals to be transmitted during a predetermined series of dialing pulses comprising a plurality ef receiving circuits selective to a predetermined identification frequency, means in said circuits for making said circuits operative and inoperative, a step mechanical contacter adapted to be advanced one step by each series of pulses from a subscribers subset, one step position of said contacter completing a circuit, and relay eans in said circuit and controlled thereby for making.

said selective circuits operative to receive said identification signals during the reception of one predetermined series of dial impulses.

5. A code controlled circuit in accordance with claim 4 in which a multi-vibrator unit is included in each of said receiving circuits for increasing the strength of said v identification signals.

6. A code controlled circuit in accordance with claim 4 in which are provided a pulsing relay having contacts responsive te dialing impulses from said subsets, a iirst relay responsive to the first of a series of impulses, a second relay responsive to the rst break between a series of impulses, the operating of lsaid second relay energizingV said step mechanical contacter to advance said contacter one step upon the de-energizatien of said second relay; 7. A code controlled circuit in accordance with claim 4 in which said relay means includes a self-locking relay for holding said selective circuits operative during said' one predetermined series of dial impulses.

8. A code controlled circuit in accordance with claim 7 in which said self-locking relay is actuated upon the break after the lirst pulse in said one predetermined series of impulses. v

9,. A gate circuit for making operative a transmission circuit during a predetermined series of a plurality of series of electrical impulses comprising a pulsing relay having contacts adapted to be actuated upon each pulse of each series of impulses, a first relay connected to one of said contacts and actuated upon the irst impulse of each series of impulses, a second relay connected toanother of said contacts and actuated upon the break after said iirst impulse of each series of impulses, a step contactor actuated by energization of said second relay and advanced one step by the de-energization of said second relay, and relay means connected to said contacter and actuated by one predetermined step position of said cen-v tactor for making said transmission circuit operative.

10. A gate circuit in accordance with claim 9 in which said relay means includes a polarizing relay for said transmission circuit, and a self-locking relay connected to and intermediate said contacter and said polarizing relay, l

S which means are provided for interconnecting said second relay and said self-locking relay, said self-locking relay being energized upon the de-energization of said pulsing relay.

12. A subset identification system comprising a subset, a central station, a line interconnecting said subset and said central station, and a pair of parallel line systems at said central station, one or" said parallel line systems including tuned circuits connected to said line for transmitting identiiication signals of different frequencies one of which is from said subset and the other of said parallel line systems including relays connected to said line for transmitting a series, a pulse signals, said pulse signals controlling the transmission of said identication signals of diierent frequencies at predetermined times.

13. A subset identification system comprising a subset, a central station, a line interconnecting said subset and said central station, and a pair of parallel line systems at said central station, one of said parallel line systems being connected to said line for transmitting identification signals of different frequencies, one of which is from said subset and the other of said parallel line systems being connected to said line for transmitting a series of pulse signals, said pulse signals controlling the transmission of said identification signals of different frequencies at pre* determined times, said first-mentioned parallel line systern including a plurality of parallel tuned circuits, each of said tuned circuits having an output circuit, and said second-mentioned parallel line system including a plurality of serially-connected relays for making operative said output circuits of said tuned circuitsy at a predeterti mined period of transmission of a signals.

14. A subset identication system comprising a subset, a central station, a line interconnectingv said subset series ot said pulse and said central station, and a pair of parallel line sys-v of tuned circuits, each having an output circuit with a relay therein, and means between said step contactor and said re'laypfor energizing all of said relays in said output circuits upon reception of a predetermined series of pulses in said second-mentioned parallel line system.

References Cited in the tile of this patent l UNITED STATES PATENTS 2,352,492 Ostline e- June 27, 1944 2,410,520 Ostline Nov. 5, 1946 2,535,765 Voss Dec. 26, 1950 2,542,592 Styrene Feb. 20, 1951 2,619,546 Myers Nov. 25, 1952 2,717,279 Matlack et al Sept. 6, 1955 2,733,297 Matlaek et al. Ian. 31, 1956 

